1. Field of the Invention
The present invention relates to a light generating module.
2. Description of the Related Art
Document 1 (Japanese Patent Application (Kokai) No. H5-323165) describes a light generating module in which a lens for providing an optical fiber with light from a semiconductor light emitting device is secured in a housing by means of a holding member (such as an xe2x80x9cL carrierxe2x80x9d). Specifically, a light generating module uses a metal frame and a lens secured thereto, and this secured lens is aligned with the L carrier and then the metal frame is welded by YAG laser within the housing.
In light generating modules that employ an L carrier, there are a number of restrictions that hinder further miniaturization of the light generating module as follows: a restriction on the outer diameter of the metal frame that holds the lens; a restriction on an area for the use of welding the L carrier by YAG laser. More particularly, these limitations hinder the miniaturization in the height direction of the light generating module.
It is therefore an object of the present invention to provide a light generating module having a structure that permits miniaturization of the height thereof.
One aspect of the present invention relates to a light generating module. The light generating module comprises a housing, a semiconductor light emitting device, a first mounting face, a second mounting face, and a lens. The housing comprises a base and an optical window. The base extends along a predetermined plane and is made from material exhibiting a first thermal conductivity. The semiconductor light emitting device is provided in the housing. The first mounting face is made from material exhibiting a thermal conductivity that is equal to or more than the first thermal conductivity. The second mounting face is made from material exhibiting a thermal conductivity equal to or more than the first thermal conductivity. The second mounting face mounts the semiconductor light emitting device. The lens is provided in the housing. The lens also comprises an installation face which is mounted on the first mounting face. The lens is used to provide light from the semiconductor light emitting device to the optical window.
Another aspect of the present invention relates to a method of manufacturing the light generating module. This method comprises a step of: (a) preparing an optical module part, a lens and an optical monitoring device, the optical module part including a semiconductor light emitting device mounted on a first mounting area in a housing, the lens comprising an installation face provided so as to be mountable on the first mounting area in the housing, and the optical monitoring device being provided to monitor light from the semiconductor light emitting device. This method comprises the step of (b) placing the optical monitoring device outside the housing and placing the lens on a second mounting area such that the semiconductor light emitting device is optically coupled to the optical monitoring device via the lens. This method comprises the step of (c) moving the lens on the second mounting area to determine a first position of the lens according to a monitoring signal from the optical monitoring device. This method comprises the step of (d) moving the lens to a second position. This method permits the condensation of light from the semiconductor light emitting device using a single lens.
The distance between the lens located in the first position and the semiconductor light emitting device is shorter than the distance between the lens located in the second position and the semiconductor light emitting device. The lens produces substantially collimated light from light from the semiconductor light emitting device in the first position.
According to the method of the present invention, the lens comprises an opposed face that is opposite to the installation face. In the step of providing the lens on the second mounting face in the housing, the lens is provided on the second mounting area using an assembly tool for holding the opposed face of the lens. The opposed face of the lens is advantageous to move the lens.
According to the method of the present invention, the lens comprises an opposed face that is opposite to the installation face. In the step of determining the first position of the lens, the lens is moved on the second mounting face using the assembly tool for holding the opposed face of the lens. The opposed face of the lens is advantageous in order to move the lens for its positioning.
According to the method of the present invention, in the step of moving the lens to the second position, the second position is shifted with respect to the first position by a predetermined value. After the lens has been shifted by the predetermined value, the lens is located at a position at which the lens can condense light from the semiconductor light emitting device. Then, the lens is located within a region in which the optical fiber may be moved in the optical alignment thereof.
The above object of the present invention, and other objects, features and advantages thereof will become more clearly apparent from the following detailed description of the preferred embodiments of the present invention that is accompanied with references to the attached drawings.